US20080170337A1 - Tunnel Magnetoresistive Effect Element and Thin-Film Magnetic Head with Tunnel Magnetoresistive Effect Read Head Element - Google Patents
Tunnel Magnetoresistive Effect Element and Thin-Film Magnetic Head with Tunnel Magnetoresistive Effect Read Head Element Download PDFInfo
- Publication number
- US20080170337A1 US20080170337A1 US11/622,603 US62260307A US2008170337A1 US 20080170337 A1 US20080170337 A1 US 20080170337A1 US 62260307 A US62260307 A US 62260307A US 2008170337 A1 US2008170337 A1 US 2008170337A1
- Authority
- US
- United States
- Prior art keywords
- layer
- magnetoresistive effect
- oxide
- tunnel magnetoresistive
- crystalline
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
- G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
- G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
- G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
- G11B5/3909—Arrangements using a magnetic tunnel junction
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
- G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
- G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
- G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/14—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates
- H01F41/30—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE]
- H01F41/302—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE] for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices
- H01F41/305—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE] for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices applying the spacer or adjusting its interface, e.g. in order to enable particular effect different from exchange coupling
- H01F41/307—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for applying magnetic films to substrates for applying nanostructures, e.g. by molecular beam epitaxy [MBE] for applying spin-exchange-coupled multilayers, e.g. nanostructured superlattices applying the spacer or adjusting its interface, e.g. in order to enable particular effect different from exchange coupling insulating or semiconductive spacer
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/80—Constructional details
- H10N50/85—Magnetic active materials
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
- G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
- G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
- G11B5/3993—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures in semi-conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F10/00—Thin magnetic films, e.g. of one-domain structure
- H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
- H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
- H01F10/3268—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
- H01F10/3272—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/11—Magnetic recording head
- Y10T428/1107—Magnetoresistive
- Y10T428/1114—Magnetoresistive having tunnel junction effect
Definitions
- the present invention relates to a tunnel magnetoresistive effect (TMR) element for reading a signal representing a magnetic field intensity in a magnetic recording medium, to a thin-film magnetic head with the TMR read head element, and to a magnetic disk drive apparatus with the thin-film magnetic head.
- TMR tunnel magnetoresistive effect
- the thin tunnel barrier layer causes problems as follows:
- U.S. Pat. Nos. 6,771,473 and 7,042,686 disclose a technique for realizing a low junction resistance and a high MR ratio. According to this technique, an intermediate layer containing at least three elements selected from Groups 2 to 17, which elements include at least one of F, O, N, C and B is used as a tunnel barrier layer.
- the TMR element includes a lower electrode layer, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on the TMR multi-layer.
- a tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- the thin-film magnetic head includes a TMR read head element which includes a lower electrode layer, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on this TMR multi-layer.
- a tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- a magnetic disk drive apparatus includes a magnetic disk, at least one thin-film magnetic head, and a support mechanism for supporting the at least one thin-film magnetic head so as to face a surface of the magnetic disk.
- the at least one thin-film magnetic head includes a TMR read head element having a lower electrode, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on the TMR multi-layer.
- a tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- the sheet resistivity RA can be reduced and a high MR ratio can be maintained while maintaining the thickness of the layer as is, due to the three-layered structure of the tunnel barrier layer where the first crystalline insulation layer, the crystalline semiconductor layer and the second crystalline insulation layer are stacked in this order.
- the TMR multi-layer includes a magnetization fixed layer, a magnetization free layer and the above-described tunnel barrier layer which is stacked between the magnetization fixed layer and the magnetization free layer.
- the magnetization fixed layer includes a soft magnetic layer for magnetic pinning and an anti-ferromagnetic layer for magnetic pinning which is exchange-coupled to the soft magnetic layer for magnetic pinning.
- the crystalline semiconductor layer is made of an oxide semiconductor material.
- This oxide semiconductor material is any one of zinc oxide (ZnO), titanium oxide (TiO 2 ), chromium oxide (CrO 2 ), tantalum oxide (Ta 2 O 5 ), indium oxide (In 2 O 3 ), tin oxide (SnO 2 ) and iron oxide (Fe 2 O 3 ) to which an impurity is added or not added.
- the crystalline insulation layer has a thickness in a range from 0.1 nm to 1.5 nm.
- first crystalline insulation layer and the second crystalline insulation layer are made of a metal oxide material.
- This metal oxide material is preferably magnesium oxide (MgO).
- first and second crystalline insulation layers have a total thickness in a range from 0.4 nm to 0.9 nm.
- the tunnel barrier layer has a thickness in a range from 0.9 nm to 2.4 nm.
- an inductive write head element is formed on the upper electrode layer of the TMR read head element.
- FIG. 1 is a perspective view schematically illustrating the main structure of a magnetic disk drive apparatus as an embodiment according to the present invention
- FIG. 2 is a perspective view illustrating an example of the structure of a head gimbal assembly (HGA) shown in FIG. 1 ;
- HGA head gimbal assembly
- FIG. 3 is a perspective view illustrating a composite thin-film magnetic head mounted at the end of the HGA of FIG. 2 ;
- FIG. 4 is a plane view illustrating a magnetic head part of the composite thin-film magnetic head of FIG. 3 , when viewed from an element forming surface side of a slider substrate;
- FIG. 5 is a central cross sectional view schematically illustrating the structure of the composite thin-film magnetic head of FIG. 3 ;
- FIG. 6 is a cross sectional view schematically illustrating the structure of a TMR read head element part of the composite thin-film magnetic head of FIG. 3 .
- FIG. 1 schematically illustrates the main structure of a magnetic disk drive apparatus according to an embodiment of the present invention.
- FIG. 2 illustrates an example of the structure of an HGA of FIG. 1 .
- FIG. 3 illustrates the composite thin-film magnetic head mounted at the end of the HGA of FIG. 2 .
- FIG. 4 illustrates the magnetic head element part of the composite thin-film magnetic head of FIG. 3 , when viewed from an element forming surface side of a slider substrate.
- a reference numeral 10 denotes a plurality of magnetic disks that rotates about the rotary axis of a spindle motor 11
- 12 denotes an assembly carriage device for positioning the composite thin-film magnetic head or magnetic head slider on the track
- 13 denotes a read/write control circuit for controlling the read/write operation of the thin-film magnetic head, respectively.
- the assembly carriage device 12 includes a plurality of drive arms 14 .
- the drive arms 14 are swingable about a pivot-bearing axis 16 by a voice coil motor (VCM) 15 , and are stacked in a direction along this axis 16 .
- VCM voice coil motor
- Each of the drive arms 14 has an HGA 17 mounted at the end thereof.
- the HGA 17 includes a magnetic head slider 12 facing the surface of each magnetic disk 10 .
- the magnetic disk drive apparatus may include only a single magnetic disk 10 , drive arm 14 and HGA 17 .
- the magnetic head slider 21 is fixed onto the end of a suspension 20 .
- the magnetic head slider 21 has a TMR read head element and an inductive write head element. Further, a terminal electrode of the magnetic head slider 21 is electrically connected to an end of a wiring member 25 .
- the suspension 20 includes mainly a load beam 22 , a flexure 23 , a base plate 24 and the wiring member 25 .
- the load beam 22 generates a load to be applied to the magnetic head slider 21 .
- the flexure 23 having elasticity is fixed onto and supported by the load beam 22 .
- the base plate 24 is arranged on the base of the load beam 22 .
- the wiring member 25 is arranged on the flexure 23 and the load beam 22 , and includes lead conductors and connection pads electrically connected to both ends of the lead conductors.
- a head drive IC chip may be mounted in the middle of the suspension 20 .
- the magnetic head slider 21 of this embodiment includes a composite thin-film magnetic head 32 and four signal terminal electrodes 33 and 34 , on an element formed surface 36 that is one side surface when an air bearing surface (ABS) 35 of the magnetic head slider serves as the bottom surface.
- the composite thin-film magnetic head 32 includes a TMR read head element 30 and an inductive write head element 31 that are mutually stacked.
- the four signal terminal electrodes 33 and 34 are connected to the TMR read head element 30 and the inductive write head element 31 .
- the positions of these terminal electrodes are not limited to those shown in FIG. 3 .
- FIG. 5 schematically illustrates the structure of the composite thin-film magnetic head according to this embodiment.
- FIG. 6 schematically illustrates the structure of the TMR read head element part of the composite thin-film magnetic head.
- FIG. 5 shows a cross sectional view in a plane that is perpendicular to the ABS of the composite thin-film magnetic head and also perpendicular to the track width direction.
- FIG. 6 shows a cross sectional view in a plane parallel to the ABS.
- the MR read head element consists of a TMR read head element
- the inductive write head element consists of a write head element with a perpendicular magnetic recording structure.
- the inductive write head element may be a write head element with a plane or horizontal magnetic recording structure.
- the ABS 35 facing the surface of the magnetic disk is formed on a slider substrate 50 made of a conductive material, such as AlTiC, Al 2 O 3 —TiC (see FIG. 3 ).
- a slider substrate 50 made of a conductive material, such as AlTiC, Al 2 O 3 —TiC (see FIG. 3 ).
- the magnetic head slider 21 hydrodynamically flies above the rotating magnetic disk with a predetermined flying height.
- An under insulation layer 51 is stacked on the element forming surface 36 of the slider substrate 50 .
- This layer 51 is made of an insulating material, such as alumina (Al 2 O 3 ) or silicon oxide (SiO 2 ), with a thickness of about 0.05 to 10 ⁇ m.
- a lower electrode layer 52 is stacked on the under insulation layer 51 .
- This layer 52 can serve also as a lower shield layer (SF) made of a metal magnetic material, such as iron aluminum silicon (FeAlSi), nickel iron (NiFe), cobalt iron (CoFe), nickel iron cobalt (NiFeCo), iron nitride (FeN), iron zirconium nitride (FeZrN), iron tantalum nitride (FeTaN), cobalt zirconium niobium (CoZrNb) or cobalt zirconium tantalum (CoZrTa).
- a TMR multi-layer 53 and an insulation layer 54 made of an insulating material, such as Al 2 O 3 or SiO 2 are stacked on the lower electrode layer 52 .
- the TMR multi-layer 53 has a multi-layered structure of a magnetization fixed layer consisting of a pinned layer and a pinning layer made of an anti-ferromagnetic material, a tunnel barrier layer, and a magnetization free layer (free layer).
- a magnetic domain control layer (not shown in FIG. 5 ) and the like for controlling the magnetic domain of the free layer is formed on the side surfaces of the TMR multi-layer 53 .
- An upper electrode layer 55 is formed on the TMR multi-layer 53 and the insulation layer 54 , and serves also as an upper shield layer (SS 1 ) made of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb, or CoZrTa.
- SS 1 a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb, or CoZrTa.
- the TMR read head element is basically composed of the lower electrode layer 52 , the TMR multi-layer 53 , the insulation layer 54 , the upper electrode layer 55 and the magnetic domain control layer.
- the structure of the TMR read head element will more specifically be described later with reference to FIG. 6 .
- the inductive write head element is formed on the TMR read head element through an insulation layer 56 a and a soft magnetic layer 56 b .
- the inductive write head element includes an insulation layer 57 , a backing coil layer 58 , a backing coil insulation layer 59 , a main magnetic pole layer 60 , an insulation gap layer 61 , a write coil layer 62 , a write coil insulation layer 63 and an auxiliary magnetic pole layer 64 .
- the insulation layer 57 is made of an insulating material, such as Al 2 O 3 or SiO 2 .
- the backing coil layer 58 is made of a conductive material, such as copper (Cu), etc.
- the backing coil insulation layer 59 is made, for example, of a heat-cured resist of novolac type.
- the main magnetic pole layer 60 is formed of a single layer film of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb or CoZrTa, or formed of a multi-layer film of any of these materials.
- the insulation gap layer 61 is made of an insulating material, such as Al 2 O 3 or SiO 2 .
- the write coil layer 62 is made of a conductive material, such as Cu.
- the insulation layer 63 is made, for example, of a heat-cured resist of novolac type.
- the auxiliary magnetic pole layer 64 is formed of a single layer film of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb or CoZrTa, or formed of a multi-layer film of any of these materials.
- a protective layer 65 made of Al 2 O 3 or SiO 2 , etc. is arranged on the inductive write head element.
- a lower metallic layer 66 and an element under layer 67 are stacked on the lower electrode layer 52 in the order described.
- the lower metallic layer 66 is made, for example, of Ta with a thickness of approximately 1 to 6 nm.
- the element under layer 67 is made, for example, of nickel chromium (NiCr), NiFe, nickel iron chromium (NiFeCr) or ruthenium (Ru) with a thickness of approximately 6 nm.
- Mn manganese
- IrMn iridium manganese
- PtMn platinum manganese
- PdPtMn palladium platinum manganese
- FeMn iron manganese
- NiMn nickel manganese
- RuRhMn ruthenium rhodium manganese
- a synthetic pinned layer is stacked on the anti-ferromagnetic layer 68 .
- This pinned layer consists of an outer pinned layer 69 , a nonmagnetic intermediate layer 70 and an inner pinned layer 71 sequentially stacked.
- the outer pinned layer 69 is made, for example, of CoFe with a thickness of about 3.0 nm.
- the nonmagnetic intermediate layer 70 is made, for example, of Ru with a thickness of about 0.8 mm.
- the inner pinned layer 71 is made, for example, of CoFe, cobalt iron silicon (CoFeSi), cobalt manganese germanium (CoMnGe), cobalt manganese silicon (CoMnSi) or cobalt manganese aluminum (CoMnAl) with a thickness of approximately 1 to 3 nm.
- the magnetic moment of the outer pinned layer 69 and the inner pinned layer 71 is mutually cancelled so as to suppress the leakage magnetic field as a whole, and the magnetization direction of the inner pinned layer 71 is securely fixed as a result of anti-ferromagnetic coupling with the outer pinned layer 69 .
- the magnetization direction of the outer pinned layer 69 is fixed due to anti-ferromagnetic coupling with the anti-ferromagnetic layer 68 .
- a tunnel barrier layer 72 is stacked on the inner pinned layer 71 .
- the tunnel barrier layer 72 has a three-layered structure of a first crystalline insulation layer 72 a , a crystalline semiconductor layer 72 b and a second crystalline insulation layer 72 c.
- the first crystalline insulation layer 72 and the second crystalline insulation layer 72 c are both made of a crystalline metal-oxide material, such as MgO with a total thickness preferably in a range from 0.4 nm to 0.9 nm.
- the crystalline semiconductor layer 72 b is preferably made of any one type of crystalline oxide semiconductor material among ZnO, TiO 2 , CrO 2 , Ta 2 O 5 , In 2 O 3 , SnO 2 and Fe 2 O 3 , or made of an n-type or p-type semiconductor material containing an impurity, which is added to the semiconductor material to form a donor or an acceptor, with a thickness preferably in a range from 0.1 nm to 1.5 nm.
- the impurity may, for example, be gallium oxide (Ga 2 O 5 ), In 2 O 3 , Al 2 O 3 , MgO or boron oxide (BO).
- a high-polarizability film 73 a and a soft magnetic film 73 b are stacked on the tunnel barrier layer 72 in this order.
- the high-polarizability film 73 a is made, for example, of CoFe with a thickness of approximately 1 nm
- the soft magnetic film 73 b is made, for example, of NiFe with a thickness in a range from 2 nm to 6 nm.
- These films 73 a and 73 b form a magnetization free layer (free layer) 73 having a two-layered structure.
- the free layer 73 may be made of a ferromagnetic alloy material, such as Fe, Co, Ni, CoFe, NiFe, NiFeCo, CoFeB or cobalt iron nickel boron (CoFeNiB).
- a ferromagnetic alloy material such as Fe, Co, Ni, CoFe, NiFe, NiFeCo, CoFeB or cobalt iron nickel boron (CoFeNiB).
- a cap layer 74 consisting of layers 74 a and 74 b is stacked on the free layer 73 .
- the layer 74 a is made, for example, of Ru with a thickness of approximately 1 nm
- the layer 74 b is made, for example, of Ta with a thickness of approximately 5 nm.
- the cap layer 74 may be made of any of Rh, Pd, silver (Ag), iridium (Ir), Pt, gold (Au) and Mg, or an alloy of these.
- the upper electrode layer 55 is stacked on the cap layer 74 .
- a hard bias layer 76 made of a hard magnetic material, such as CoPt is formed on the both sides of the TMR multi-layer in the track width direction through insulation layers 75 of for example Al 2 O 3 or SiO 2 .
- This hard bias layer 76 is used for applying a bias magnetic field for magnetic domain control to the free layer 73 .
- a stacked structure of a hard magnetic layer and an anti-ferromagnetic layer may be provided.
- the tunnel barrier layer 72 has a three-layered structure of the first crystalline insulation layer 72 a , the crystalline semiconductor layer 72 b and the second crystalline insulation layer 72 c , stacked in this order. Due to this structure, the sheet resistivity RA can be decreased while maintaining the film thickness, and also a high MR ratio can be maintained.
- a plurality of samples of the tunnel barrier layer having a three-layered structure with layers of different thicknesses are prepared. Then, the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin are measured. In this case, a MgO layer is used as the first crystalline insulation layer 72 a and the second crystalline insulation layer 72 c , while a ZnO layer is used as the crystalline semiconductor layer 72 b . Tables 1 to 3 show the results.
- the interlayer coupling magnetic field Hin is an index indicating a magnetic coupling degree between the inner pinned layer 71 and the free layer 73 .
- the value of the interlayer coupling magnetic field Hin is high when the free layer is highly effected by the pinned layer.
- the value of this interlayer coupling magnetic field Hin is preferably low.
- the sheet resistivity RA is required to be in a range from 0.3 ⁇ m 2 to 5.0 ⁇ m 2 . If the sheet resistivity RA is lower than 0.3 ⁇ m 2 , the insulation of the tunnel barrier layer is deteriorated. This may result in a reduction in the life of the element. If the sheet resistivity RA is greater than 5.0 ⁇ m 2 , the element resistance becomes too high. As a result, the head SN ratio may possibly be decreased at high frequencies, and then a preamplifier outputs may possibly be saturated.
- the MR ratio it is required that the MR ratio be 30% or more. If the MR ratio is lower than 30%, sufficient head outputs cannot be obtained, in the case of a small element size. As a result, there is the possibility of a decrease in the head SN ratio.
- Table 1 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the thickness of the ZnO layer.
- the tunnel barrier layer is formed of a single MgO layer.
- Sample 1 is not desirable, because Hin is too high.
- Samples 2 and 3 are not desirable, because their RA is greater than 5.0 ⁇ m 2 .
- the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer.
- RA is 5.0 ⁇ m 2 or less
- the MR ratio is 31% or more
- Hin is 15 Oe or less.
- their thickness is in a desirable range.
- RA is greater than 5.0 ⁇ m 2
- the MR ratio is lower than 30%.
- samples 11 and 12 are not desirable samples.
- the thickness of the ZnO layer is desirably in a range from 0.1 nm to 1.5 nm.
- Table 2 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the total thickness of the first MgO layer and the second MgO layer.
- the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer.
- Sample 13 is not desirable, because the MR ratio is lower than 30%.
- Sample 16 is not desirable, because RA is greater than 5.0 ⁇ m 2 .
- Samples 14 , 9 and 15 have a desirable thickness, because RA is 5.0 ⁇ m 2 or less, the MR ratio is 32% or more and Hin is 9 Oe or less.
- the total thickness of the first MgO layer and the second MgO layer is preferably in a range from 0.4 nm to 0.9 nm.
- Table 3 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the total thickness of the tunnel barrier layer.
- the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer.
- Sample 17 is not desirable, because the MR ratio is lower than 30% and Hin is quite high. Samples 11 and 12 are not desirable, because RA is greater than 5.0 ⁇ m 2 and the MR ratio is lower than 30%.
- Samples 18 and 4 to 10 have a desirable thickness, because RA is 5.0 ⁇ m 2 or less, the MR ratio is 30% or more and Hin is 15 Oe or less.
- the thickness of the tunnel barrier layer is preferably in a range from 0.9 nm to 2.4 nm.
Landscapes
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Hall/Mr Elements (AREA)
- Magnetic Heads (AREA)
Abstract
Description
- 1. Field of the Invention
- The present invention relates to a tunnel magnetoresistive effect (TMR) element for reading a signal representing a magnetic field intensity in a magnetic recording medium, to a thin-film magnetic head with the TMR read head element, and to a magnetic disk drive apparatus with the thin-film magnetic head.
- 2. Description of the Related Art
- In order to satisfy the demand for higher recording density and downsizing in a hard disk drive (HDD) apparatus, higher sensitivity and larger output of a thin-film magnetic head are required. In order to meet this requirement, a thin-film magnetic head with a TMR read head element has been put to practical use.
- In the thin-film magnetic head with such TMR read head element, it is necessary to decrease both resistance and capacitance of a read head circuit in order to be adaptive at high frequencies. Decreasing the resistance of the TMR read head element itself is effective to do this. This can easily be accomplished by reducing a thickness of a tunnel barrier layer.
- However, the thin tunnel barrier layer causes problems as follows:
- (1) the life of an element is reduced due to an increase in pin-holes in the tunnel barrier layer;
- (2) a magnetic coupling between a magnetization fixed layer and a magnetization free layer in a TMR multiplayer increases causing an increase in noise at read output;
- (3) it is difficult to control a process of fabricating a uniformly thin tunnel barrier layer; and
- (4) a magnetoresistive effect (MR) ratio decreases.
- Therefore, it is necessary to reduce a sheet resistivity of the tunnel barrier layer without making it thin. In addition, it is required to maintain a high MR ratio.
- U.S. Pat. Nos. 6,771,473 and 7,042,686 disclose a technique for realizing a low junction resistance and a high MR ratio. According to this technique, an intermediate layer containing at least three elements selected from Groups 2 to 17, which elements include at least one of F, O, N, C and B is used as a tunnel barrier layer.
- It is therefore an object of the present invention to provide a TMR element with a new structure having a tunnel barrier layer for obtaining a low sheet resistivity without reducing its thickness, a thin-film magnetic head having the TMR read head element, and a magnetic disk drive apparatus including the thin-film magnetic head.
- According to the present invention, the TMR element includes a lower electrode layer, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on the TMR multi-layer. A tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- Also, according to the present invention, the thin-film magnetic head includes a TMR read head element which includes a lower electrode layer, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on this TMR multi-layer. A tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- According to the present invention, further, a magnetic disk drive apparatus includes a magnetic disk, at least one thin-film magnetic head, and a support mechanism for supporting the at least one thin-film magnetic head so as to face a surface of the magnetic disk. The at least one thin-film magnetic head includes a TMR read head element having a lower electrode, a TMR multi-layer stacked on the lower electrode layer, and an upper electrode layer stacked on the TMR multi-layer. A tunnel barrier layer of the TMR multi-layer has a three-layered structure of a first crystalline insulation layer, a crystalline semiconductor layer and a second crystalline insulation layer stacked in this order.
- The sheet resistivity RA can be reduced and a high MR ratio can be maintained while maintaining the thickness of the layer as is, due to the three-layered structure of the tunnel barrier layer where the first crystalline insulation layer, the crystalline semiconductor layer and the second crystalline insulation layer are stacked in this order.
- It is preferred that the TMR multi-layer includes a magnetization fixed layer, a magnetization free layer and the above-described tunnel barrier layer which is stacked between the magnetization fixed layer and the magnetization free layer.
- It is also preferred that the magnetization fixed layer includes a soft magnetic layer for magnetic pinning and an anti-ferromagnetic layer for magnetic pinning which is exchange-coupled to the soft magnetic layer for magnetic pinning.
- It is further preferred that the crystalline semiconductor layer is made of an oxide semiconductor material. This oxide semiconductor material is any one of zinc oxide (ZnO), titanium oxide (TiO2), chromium oxide (CrO2), tantalum oxide (Ta2O5), indium oxide (In2O3), tin oxide (SnO2) and iron oxide (Fe2O3) to which an impurity is added or not added.
- It is also preferred that the crystalline insulation layer has a thickness in a range from 0.1 nm to 1.5 nm.
- It is further preferred that the first crystalline insulation layer and the second crystalline insulation layer are made of a metal oxide material. This metal oxide material is preferably magnesium oxide (MgO).
- It is also preferred that the first and second crystalline insulation layers have a total thickness in a range from 0.4 nm to 0.9 nm.
- It is further preferred that the tunnel barrier layer has a thickness in a range from 0.9 nm to 2.4 nm.
- It is also preferred that an inductive write head element is formed on the upper electrode layer of the TMR read head element.
- Other objects and advantages of the present invention will become apparent from the following description of preferred embodiment of the present invention with reference to accompanying drawings.
-
FIG. 1 is a perspective view schematically illustrating the main structure of a magnetic disk drive apparatus as an embodiment according to the present invention; -
FIG. 2 is a perspective view illustrating an example of the structure of a head gimbal assembly (HGA) shown inFIG. 1 ; -
FIG. 3 is a perspective view illustrating a composite thin-film magnetic head mounted at the end of the HGA ofFIG. 2 ; -
FIG. 4 is a plane view illustrating a magnetic head part of the composite thin-film magnetic head ofFIG. 3 , when viewed from an element forming surface side of a slider substrate; -
FIG. 5 is a central cross sectional view schematically illustrating the structure of the composite thin-film magnetic head ofFIG. 3 ; and -
FIG. 6 is a cross sectional view schematically illustrating the structure of a TMR read head element part of the composite thin-film magnetic head ofFIG. 3 . -
FIG. 1 schematically illustrates the main structure of a magnetic disk drive apparatus according to an embodiment of the present invention.FIG. 2 illustrates an example of the structure of an HGA ofFIG. 1 .FIG. 3 illustrates the composite thin-film magnetic head mounted at the end of the HGA ofFIG. 2 .FIG. 4 illustrates the magnetic head element part of the composite thin-film magnetic head ofFIG. 3 , when viewed from an element forming surface side of a slider substrate. - In
FIG. 1 , areference numeral 10 denotes a plurality of magnetic disks that rotates about the rotary axis of aspindle motor - The
assembly carriage device 12 includes a plurality ofdrive arms 14. Thedrive arms 14 are swingable about a pivot-bearingaxis 16 by a voice coil motor (VCM) 15, and are stacked in a direction along thisaxis 16. Each of thedrive arms 14 has anHGA 17 mounted at the end thereof. The HGA 17 includes amagnetic head slider 12 facing the surface of eachmagnetic disk 10. In modifications, the magnetic disk drive apparatus may include only a singlemagnetic disk 10,drive arm 14 andHGA 17. - As shown in
FIG. 2 , in the HGA, themagnetic head slider 21 is fixed onto the end of asuspension 20. Themagnetic head slider 21 has a TMR read head element and an inductive write head element. Further, a terminal electrode of themagnetic head slider 21 is electrically connected to an end of awiring member 25. - The
suspension 20 includes mainly aload beam 22, aflexure 23, abase plate 24 and thewiring member 25. Theload beam 22 generates a load to be applied to themagnetic head slider 21. Theflexure 23 having elasticity is fixed onto and supported by theload beam 22. Thebase plate 24 is arranged on the base of theload beam 22. Thewiring member 25 is arranged on theflexure 23 and theload beam 22, and includes lead conductors and connection pads electrically connected to both ends of the lead conductors. - It is obvious that the structure of the suspension according to the present invention is not limited to the above. Though not illustrated, a head drive IC chip may be mounted in the middle of the
suspension 20. - As shown in
FIGS. 3 and 4 , themagnetic head slider 21 of this embodiment includes a composite thin-filmmagnetic head 32 and foursignal terminal electrodes surface 36 that is one side surface when an air bearing surface (ABS) 35 of the magnetic head slider serves as the bottom surface. The composite thin-filmmagnetic head 32 includes a TMRread head element 30 and an inductivewrite head element 31 that are mutually stacked. The foursignal terminal electrodes head element 30 and the inductivewrite head element 31. The positions of these terminal electrodes are not limited to those shown inFIG. 3 . -
FIG. 5 schematically illustrates the structure of the composite thin-film magnetic head according to this embodiment.FIG. 6 schematically illustrates the structure of the TMR read head element part of the composite thin-film magnetic head.FIG. 5 shows a cross sectional view in a plane that is perpendicular to the ABS of the composite thin-film magnetic head and also perpendicular to the track width direction.FIG. 6 shows a cross sectional view in a plane parallel to the ABS. In this embodiment, the MR read head element consists of a TMR read head element, and the inductive write head element consists of a write head element with a perpendicular magnetic recording structure. However, the inductive write head element may be a write head element with a plane or horizontal magnetic recording structure. - The
ABS 35 facing the surface of the magnetic disk is formed on aslider substrate 50 made of a conductive material, such as AlTiC, Al2O3—TiC (seeFIG. 3 ). In operation, themagnetic head slider 21 hydrodynamically flies above the rotating magnetic disk with a predetermined flying height. An underinsulation layer 51 is stacked on theelement forming surface 36 of theslider substrate 50. Thislayer 51 is made of an insulating material, such as alumina (Al2O3) or silicon oxide (SiO2), with a thickness of about 0.05 to 10 μm. Alower electrode layer 52 is stacked on the underinsulation layer 51. Thislayer 52 can serve also as a lower shield layer (SF) made of a metal magnetic material, such as iron aluminum silicon (FeAlSi), nickel iron (NiFe), cobalt iron (CoFe), nickel iron cobalt (NiFeCo), iron nitride (FeN), iron zirconium nitride (FeZrN), iron tantalum nitride (FeTaN), cobalt zirconium niobium (CoZrNb) or cobalt zirconium tantalum (CoZrTa). ATMR multi-layer 53 and aninsulation layer 54 made of an insulating material, such as Al2O3 or SiO2 are stacked on thelower electrode layer 52. - The
TMR multi-layer 53 has a multi-layered structure of a magnetization fixed layer consisting of a pinned layer and a pinning layer made of an anti-ferromagnetic material, a tunnel barrier layer, and a magnetization free layer (free layer). A magnetic domain control layer (not shown inFIG. 5 ) and the like for controlling the magnetic domain of the free layer is formed on the side surfaces of theTMR multi-layer 53. - An
upper electrode layer 55 is formed on theTMR multi-layer 53 and theinsulation layer 54, and serves also as an upper shield layer (SS1) made of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb, or CoZrTa. - The TMR read head element is basically composed of the
lower electrode layer 52, theTMR multi-layer 53, theinsulation layer 54, theupper electrode layer 55 and the magnetic domain control layer. The structure of the TMR read head element will more specifically be described later with reference toFIG. 6 . - An inductive write head element is formed on the TMR read head element through an
insulation layer 56 a and a softmagnetic layer 56 b. The inductive write head element includes aninsulation layer 57, abacking coil layer 58, a backingcoil insulation layer 59, a mainmagnetic pole layer 60, aninsulation gap layer 61, awrite coil layer 62, a writecoil insulation layer 63 and an auxiliarymagnetic pole layer 64. Theinsulation layer 57 is made of an insulating material, such as Al2O3 or SiO2. Thebacking coil layer 58 is made of a conductive material, such as copper (Cu), etc. The backingcoil insulation layer 59 is made, for example, of a heat-cured resist of novolac type. The mainmagnetic pole layer 60 is formed of a single layer film of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb or CoZrTa, or formed of a multi-layer film of any of these materials. Theinsulation gap layer 61 is made of an insulating material, such as Al2O3 or SiO2. Thewrite coil layer 62 is made of a conductive material, such as Cu. Theinsulation layer 63 is made, for example, of a heat-cured resist of novolac type. The auxiliarymagnetic pole layer 64 is formed of a single layer film of a metallic magnetic material, such as FeAlSi, NiFe, CoFe, NiFeCo, FeN, FeZrN, FeTaN, CoZrNb or CoZrTa, or formed of a multi-layer film of any of these materials. Aprotective layer 65 made of Al2O3 or SiO2, etc. is arranged on the inductive write head element. - The structure of the TMR read head element according to this embodiment will now be described with reference to
FIG. 6 . In this illustration, for the sake of clarity in the description, names and exemplary materials (but not limited to) of the layers follow corresponding reference numerals. - A lower metallic layer 66 and an element under layer 67 are stacked on the
lower electrode layer 52 in the order described. The lower metallic layer 66 is made, for example, of Ta with a thickness of approximately 1 to 6 nm. The element under layer 67 is made, for example, of nickel chromium (NiCr), NiFe, nickel iron chromium (NiFeCr) or ruthenium (Ru) with a thickness of approximately 6 nm. An anti-ferromagnetic layer (pinning layer) 68 made of a manganese (Mn) alloy, such as iridium manganese (IrMn), platinum manganese (PtMn), palladium platinum manganese (PdPtMn), iron manganese (FeMn), nickel manganese (NiMn), ruthenium rhodium manganese (RuRhMn), rhodium manganese (RhMn) or chromium manganese platinum (CrMnPt) with a thickness of about 5 to 15 nm, preferably approximately 7 nm is stacked on the element under layer 67. - A synthetic pinned layer is stacked on the
anti-ferromagnetic layer 68. This pinned layer consists of an outer pinnedlayer 69, a nonmagnetic intermediate layer 70 and an inner pinned layer 71 sequentially stacked. The outer pinnedlayer 69 is made, for example, of CoFe with a thickness of about 3.0 nm. The nonmagnetic intermediate layer 70 is made, for example, of Ru with a thickness of about 0.8 mm. The inner pinned layer 71 is made, for example, of CoFe, cobalt iron silicon (CoFeSi), cobalt manganese germanium (CoMnGe), cobalt manganese silicon (CoMnSi) or cobalt manganese aluminum (CoMnAl) with a thickness of approximately 1 to 3 nm. In the synthetic pinned layer, the magnetic moment of the outer pinnedlayer 69 and the inner pinned layer 71 is mutually cancelled so as to suppress the leakage magnetic field as a whole, and the magnetization direction of the inner pinned layer 71 is securely fixed as a result of anti-ferromagnetic coupling with the outer pinnedlayer 69. The magnetization direction of the outer pinnedlayer 69 is fixed due to anti-ferromagnetic coupling with theanti-ferromagnetic layer 68. - A
tunnel barrier layer 72 is stacked on the inner pinned layer 71. In this embodiment, thetunnel barrier layer 72 has a three-layered structure of a firstcrystalline insulation layer 72 a, acrystalline semiconductor layer 72 b and a secondcrystalline insulation layer 72 c. - The first
crystalline insulation layer 72 and the secondcrystalline insulation layer 72 c are both made of a crystalline metal-oxide material, such as MgO with a total thickness preferably in a range from 0.4 nm to 0.9 nm. Thecrystalline semiconductor layer 72 b is preferably made of any one type of crystalline oxide semiconductor material among ZnO, TiO2, CrO2, Ta2O5, In2O3, SnO2 and Fe2O3, or made of an n-type or p-type semiconductor material containing an impurity, which is added to the semiconductor material to form a donor or an acceptor, with a thickness preferably in a range from 0.1 nm to 1.5 nm. The impurity may, for example, be gallium oxide (Ga2O5), In2O3, Al2O3, MgO or boron oxide (BO). - Due to the crystalline material of each layer of the three-layered structure, spin polarized electrons coherently tunnel without the loss of spin information. Also, an adequate impurity is doped to the semiconductor material, thereby easily adjusting the sheet resistivity RA.
- A high-
polarizability film 73 a and a softmagnetic film 73 b are stacked on thetunnel barrier layer 72 in this order. The high-polarizability film 73 a is made, for example, of CoFe with a thickness of approximately 1 nm, while the softmagnetic film 73 b is made, for example, of NiFe with a thickness in a range from 2 nm to 6 nm. Thesefilms free layer 73 may be made of a ferromagnetic alloy material, such as Fe, Co, Ni, CoFe, NiFe, NiFeCo, CoFeB or cobalt iron nickel boron (CoFeNiB). - A
cap layer 74 consisting oflayers free layer 73. Thelayer 74 a is made, for example, of Ru with a thickness of approximately 1 nm, while thelayer 74 b is made, for example, of Ta with a thickness of approximately 5 nm. Other than the above materials, thecap layer 74 may be made of any of Rh, Pd, silver (Ag), iridium (Ir), Pt, gold (Au) and Mg, or an alloy of these. - The
upper electrode layer 55 is stacked on thecap layer 74. - A
hard bias layer 76 made of a hard magnetic material, such as CoPt is formed on the both sides of the TMR multi-layer in the track width direction throughinsulation layers 75 of for example Al2O3 or SiO2. Thishard bias layer 76 is used for applying a bias magnetic field for magnetic domain control to thefree layer 73. In place of the hard bias layer, a stacked structure of a hard magnetic layer and an anti-ferromagnetic layer may be provided. - As explained above, in this embodiment, the
tunnel barrier layer 72 has a three-layered structure of the firstcrystalline insulation layer 72 a, thecrystalline semiconductor layer 72 b and the secondcrystalline insulation layer 72 c, stacked in this order. Due to this structure, the sheet resistivity RA can be decreased while maintaining the film thickness, and also a high MR ratio can be maintained. - A plurality of samples of the tunnel barrier layer having a three-layered structure with layers of different thicknesses are prepared. Then, the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin are measured. In this case, a MgO layer is used as the first
crystalline insulation layer 72 a and the secondcrystalline insulation layer 72 c, while a ZnO layer is used as thecrystalline semiconductor layer 72 b. Tables 1 to 3 show the results. - Note that the interlayer coupling magnetic field Hin is an index indicating a magnetic coupling degree between the inner pinned layer 71 and the
free layer 73. The value of the interlayer coupling magnetic field Hin is high when the free layer is highly effected by the pinned layer. The value of this interlayer coupling magnetic field Hin is preferably low. - In general, the sheet resistivity RA is required to be in a range from 0.3 Ωμm2 to 5.0 Ωμm2. If the sheet resistivity RA is lower than 0.3 Ωμm2, the insulation of the tunnel barrier layer is deteriorated. This may result in a reduction in the life of the element. If the sheet resistivity RA is greater than 5.0 Ωμm2, the element resistance becomes too high. As a result, the head SN ratio may possibly be decreased at high frequencies, and then a preamplifier outputs may possibly be saturated.
- In general, it is required that the MR ratio be 30% or more. If the MR ratio is lower than 30%, sufficient head outputs cannot be obtained, in the case of a small element size. As a result, there is the possibility of a decrease in the head SN ratio.
- Table 1 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the thickness of the ZnO layer.
-
TABLE 1 Total Thickness Thickness Thickness of Thickness of of Interlayer First of Second Tunnel Sheet Coupling MgO ZnO MgO Barrier Resistivity MR Magnetic Layer Layer Layer Layer RA Ratio Field (nm) (nm) (nm) (nm) (Ωμm2) (%) Hin (Oe) Sample 1 0.8 0 0 0.8 1.90 55 30 Sample 2 1.5 0 0 1.5 6.50 75 6 Sample 3 2.4 0 0 2.4 14.50 80 8 Sample 4 0.5 0.1 0.4 1.0 1.95 54 15 Sample 5 0.5 0.2 0.4 1.1 1.98 52 9 Sample 6 0.5 0.5 0.4 1.4 2.50 50 7 Sample 7 0.5 0.8 0.4 1.7 3.40 45 9 Sample 8 0.3 1.2 0.3 1.8 1.50 38 10 Sample 9 0.3 1.5 0.3 2.1 2.40 34 8 Sample 100.5 1.5 0.4 2.4 5.00 31 10 Sample 110.5 1.7 0.4 2.6 5.50 25 9 Sample 120.5 2.0 0.4 2.9 6.25 18 7 - In samples 1 to 3, the tunnel barrier layer is formed of a single MgO layer. Sample 1 is not desirable, because Hin is too high. Samples 2 and 3 are not desirable, because their RA is greater than 5.0 Ωμm2.
- In samples 4 to 12, the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer. In samples 4 to 10, RA is 5.0 Ωμm2 or less, the MR ratio is 31% or more, and Hin is 15 Oe or less. Thus, their thickness is in a desirable range. In
samples samples - Therefore, the thickness of the ZnO layer is desirably in a range from 0.1 nm to 1.5 nm.
- Table 2 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the total thickness of the first MgO layer and the second MgO layer. In samples of Table 2, the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer.
-
TABLE 2 Total Thickness Thickness Thickness of Thickness of of Interlayer First of Second Tunnel Sheet Coupling MgO ZnO MgO Barrier Resistivity MR Magnetic Layer Layer Layer Layer RA Ratio Field (nm) (nm) (nm) (nm) (Ωμm2) (%) Hin (Oe) Sample 130.1 1.5 0.1 1.7 1.85 29 9 Sample 140.2 1.5 0.2 1.9 1.92 32 9 Sample 9 0.3 1.5 0.3 2.1 2.40 34 8 Sample 150.5 1.5 0.4 2.4 5.00 50 7 Sample 160.6 1.5 0.4 2.5 6.50 55 8 -
Sample 13 is not desirable, because the MR ratio is lower than 30%.Sample 16 is not desirable, because RA is greater than 5.0 Ωμm2. -
Samples - Therefore, the total thickness of the first MgO layer and the second MgO layer is preferably in a range from 0.4 nm to 0.9 nm.
- Table 3 shows the dependence of the sheet resistivity RA, MR ratio and interlayer coupling magnetic field Hin, on the total thickness of the tunnel barrier layer. In samples of Table 3, the tunnel barrier layer has a three-layered structure of a MgO layer/ZnO layer/MgO layer.
-
TABLE 3 Total Thickness Thickness Thickness of Thickness of of Interlayer First of Second Tunnel Sheet Coupling MgO ZnO MgO Barrier Resistivity MR Magnetic Layer Layer Layer Layer RA Ratio Field (nm) (nm) (nm) (nm) (Ωμm2) (%) Hin (Oe) Sample 170.2 0.5 0.1 0.8 0.25 16 28 Sample 18 0.2 0.5 0.2 0.9 0.40 30 13 Sample 4 0.5 0.1 0.4 1.0 1.95 54 15 Sample 5 0.5 0.2 0.4 1.1 1.98 52 9 Sample 6 0.5 0.5 0.4 1.4 2.50 50 7 Sample 7 0.5 0.8 0.4 1.7 3.40 45 9 Sample 8 0.3 1.2 0.3 1.8 1.50 38 10 Sample 9 0.3 1.5 0.3 2.1 2.40 34 8 Sample 100.5 1.5 0.4 2.4 5.00 31 10 Sample 110.5 1.7 0.4 2.6 5.50 25 9 Sample 120.5 2.0 0.4 2.9 6.25 18 7 -
Sample 17 is not desirable, because the MR ratio is lower than 30% and Hin is quite high.Samples - Samples 18 and 4 to 10 have a desirable thickness, because RA is 5.0 Ωμm2 or less, the MR ratio is 30% or more and Hin is 15 Oe or less.
- Therefore, the thickness of the tunnel barrier layer is preferably in a range from 0.9 nm to 2.4 nm.
- Many widely different embodiments of the present invention may be constructed without departing from the spirit and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in the specification, except as defined in the appended claims.
Claims (29)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/622,603 US7715156B2 (en) | 2007-01-12 | 2007-01-12 | Tunnel magnetoresistive effect element and thin-film magnetic head with tunnel magnetoresistive effect read head element |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/622,603 US7715156B2 (en) | 2007-01-12 | 2007-01-12 | Tunnel magnetoresistive effect element and thin-film magnetic head with tunnel magnetoresistive effect read head element |
Publications (2)
Publication Number | Publication Date |
---|---|
US20080170337A1 true US20080170337A1 (en) | 2008-07-17 |
US7715156B2 US7715156B2 (en) | 2010-05-11 |
Family
ID=39617574
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/622,603 Active 2029-02-07 US7715156B2 (en) | 2007-01-12 | 2007-01-12 | Tunnel magnetoresistive effect element and thin-film magnetic head with tunnel magnetoresistive effect read head element |
Country Status (1)
Country | Link |
---|---|
US (1) | US7715156B2 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080198513A1 (en) * | 2007-02-20 | 2008-08-21 | Shinji Hara | MAGNETIC THIN FILM HAVING NON-MAGNETIC SPACER LAYER THAT IS PROVIDED WITH SnO2 LAYER |
US20080232002A1 (en) * | 2007-03-22 | 2008-09-25 | Freescale Semiconductor, Inc. | Mram tunnel barrier structure and methods |
US20080239588A1 (en) * | 2007-03-26 | 2008-10-02 | Kabushiki Kaisha Toshiba | Magneto-resistance effect element, magnetic head, and magnetic recording/reproducing device |
US20090207532A1 (en) * | 2008-02-15 | 2009-08-20 | Fujitsu Limited | Magneto resistance effect device, head slider, magnetic information storage apparatus, and magneto resistance effect memory |
US20100055452A1 (en) * | 2007-05-11 | 2010-03-04 | Alps Electric Co., Ltd. | Tunneling magnetic sensing element including mgo film as insulating barrier layer |
US20150214275A1 (en) * | 2014-01-24 | 2015-07-30 | National Taiwan University | Magnetic tunnel junction with superlattice barriers |
US20170278706A1 (en) * | 2014-09-02 | 2017-09-28 | Flosfia Inc. | Multilayer structure, method for manufacturing same, semiconductor device, and crystalline film |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008135432A (en) * | 2006-11-27 | 2008-06-12 | Tdk Corp | Tunnel magnetoresistive effect element and manufacturing method thereof |
US7916431B2 (en) * | 2007-08-27 | 2011-03-29 | Tdk Corporation | Magnetoresistive element including insulating film touching periphery of spacer layer |
JP2009076778A (en) * | 2007-09-21 | 2009-04-09 | Fujitsu Ltd | Magnetoresistance effect element and magnetoresistive device |
US20110031569A1 (en) * | 2009-08-10 | 2011-02-10 | Grandis, Inc. | Method and system for providing magnetic tunneling junction elements having improved performance through capping layer induced perpendicular anisotropy and memories using such magnetic elements |
US8568602B2 (en) | 2011-01-19 | 2013-10-29 | HGST Netherlands B.V. | Method of manufacturing a magnetic read sensor having a low resistance cap structure |
JP2014074606A (en) * | 2012-10-03 | 2014-04-24 | Toshiba Corp | Pressure sensor, acoustic microphone, blood pressure sensor and touch panel |
US9263068B1 (en) | 2014-11-05 | 2016-02-16 | International Business Machines Corporation | Magnetic read head having a CPP MR sensor electrically isolated from a top shield |
US9280991B1 (en) | 2015-01-07 | 2016-03-08 | International Business Machines Corporation | TMR head design with insulative layers for shorting mitigation |
US9607635B1 (en) | 2016-04-22 | 2017-03-28 | International Business Machines Corporation | Current perpendicular-to-plane sensors having hard spacers |
US9947348B1 (en) | 2017-02-28 | 2018-04-17 | International Business Machines Corporation | Tunnel magnetoresistive sensor having leads supporting three-dimensional current flow |
US9997180B1 (en) | 2017-03-22 | 2018-06-12 | International Business Machines Corporation | Hybrid dielectric gap liner and magnetic shield liner |
US10803889B2 (en) | 2019-02-21 | 2020-10-13 | International Business Machines Corporation | Apparatus with data reader sensors more recessed than servo reader sensor |
US11074930B1 (en) | 2020-05-11 | 2021-07-27 | International Business Machines Corporation | Read transducer structure having an embedded wear layer between thin and thick shield portions |
US11114117B1 (en) | 2020-05-20 | 2021-09-07 | International Business Machines Corporation | Process for manufacturing magnetic head having a servo read transducer structure with dielectric gap liner and a data read transducer structure with an embedded wear layer between thin and thick shield portions |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020114112A1 (en) * | 2001-02-06 | 2002-08-22 | Eiji Nakashio | Magnetic tunnel element and its manufacturing method, thin-film magnetic head, magnetic memory and magnetic sensor |
US20030214762A1 (en) * | 2002-05-14 | 2003-11-20 | Manish Sharma | Magnetic field detection sensor |
US6771473B2 (en) * | 2001-01-22 | 2004-08-03 | Matsushita Electric Industrial Co., Ltd. | Magnetoresistive element and method for producing the same |
US20060018057A1 (en) * | 2004-07-26 | 2006-01-26 | Yiming Huai | Magnetic tunnel junction having diffusion stop layer |
US20070070553A1 (en) * | 2005-09-27 | 2007-03-29 | Canon Anelva Corporation | Magnetoresistance effect device |
US7602000B2 (en) * | 2003-11-19 | 2009-10-13 | International Business Machines Corporation | Spin-current switched magnetic memory element suitable for circuit integration and method of fabricating the memory element |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3576111B2 (en) | 2001-03-12 | 2004-10-13 | 株式会社東芝 | Magnetoresistance effect element |
JP3565268B2 (en) | 2001-06-22 | 2004-09-15 | 株式会社東芝 | Magnetoresistive element, magnetic head, and magnetic reproducing device |
JP4292128B2 (en) | 2004-09-07 | 2009-07-08 | キヤノンアネルバ株式会社 | Method for manufacturing magnetoresistive element |
JP2006093432A (en) | 2004-09-24 | 2006-04-06 | Sony Corp | Memory element and memory |
-
2007
- 2007-01-12 US US11/622,603 patent/US7715156B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6771473B2 (en) * | 2001-01-22 | 2004-08-03 | Matsushita Electric Industrial Co., Ltd. | Magnetoresistive element and method for producing the same |
US7042686B2 (en) * | 2001-01-22 | 2006-05-09 | Matsushita Electric Industrial Co., Ltd. | Magnetoresistive element and method for producing the same |
US20020114112A1 (en) * | 2001-02-06 | 2002-08-22 | Eiji Nakashio | Magnetic tunnel element and its manufacturing method, thin-film magnetic head, magnetic memory and magnetic sensor |
US6760201B2 (en) * | 2001-02-06 | 2004-07-06 | Sony Corporation | Magnetic tunnel element and its manufacturing method, thin-film magnetic head, magnetic memory and magnetic sensor |
US20030214762A1 (en) * | 2002-05-14 | 2003-11-20 | Manish Sharma | Magnetic field detection sensor |
US7602000B2 (en) * | 2003-11-19 | 2009-10-13 | International Business Machines Corporation | Spin-current switched magnetic memory element suitable for circuit integration and method of fabricating the memory element |
US20060018057A1 (en) * | 2004-07-26 | 2006-01-26 | Yiming Huai | Magnetic tunnel junction having diffusion stop layer |
US7576956B2 (en) * | 2004-07-26 | 2009-08-18 | Grandis Inc. | Magnetic tunnel junction having diffusion stop layer |
US20070070553A1 (en) * | 2005-09-27 | 2007-03-29 | Canon Anelva Corporation | Magnetoresistance effect device |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080198513A1 (en) * | 2007-02-20 | 2008-08-21 | Shinji Hara | MAGNETIC THIN FILM HAVING NON-MAGNETIC SPACER LAYER THAT IS PROVIDED WITH SnO2 LAYER |
US7859798B2 (en) * | 2007-02-20 | 2010-12-28 | Tdk Corporation | Magnetic thin film having non-magnetic spacer layer that is provided with SnO2 layer |
US20080232002A1 (en) * | 2007-03-22 | 2008-09-25 | Freescale Semiconductor, Inc. | Mram tunnel barrier structure and methods |
US7888756B2 (en) * | 2007-03-22 | 2011-02-15 | Everspin Technologies, Inc. | MRAM tunnel barrier structure and methods |
US20080239588A1 (en) * | 2007-03-26 | 2008-10-02 | Kabushiki Kaisha Toshiba | Magneto-resistance effect element, magnetic head, and magnetic recording/reproducing device |
US20100055452A1 (en) * | 2007-05-11 | 2010-03-04 | Alps Electric Co., Ltd. | Tunneling magnetic sensing element including mgo film as insulating barrier layer |
US8124253B2 (en) * | 2007-05-11 | 2012-02-28 | Alps Electric Co., Ltd. | Tunneling magnetic sensing element including MGO film as insulating barrier layer |
US20090207532A1 (en) * | 2008-02-15 | 2009-08-20 | Fujitsu Limited | Magneto resistance effect device, head slider, magnetic information storage apparatus, and magneto resistance effect memory |
US20150214275A1 (en) * | 2014-01-24 | 2015-07-30 | National Taiwan University | Magnetic tunnel junction with superlattice barriers |
US9437655B2 (en) * | 2014-01-24 | 2016-09-06 | National Taiwan University | Magnetic tunnel junction with superlattice barriers |
US20170278706A1 (en) * | 2014-09-02 | 2017-09-28 | Flosfia Inc. | Multilayer structure, method for manufacturing same, semiconductor device, and crystalline film |
US10043664B2 (en) * | 2014-09-02 | 2018-08-07 | Flosfia Inc. | Multilayer structure, method for manufacturing same, semiconductor device, and crystalline film |
Also Published As
Publication number | Publication date |
---|---|
US7715156B2 (en) | 2010-05-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7715156B2 (en) | Tunnel magnetoresistive effect element and thin-film magnetic head with tunnel magnetoresistive effect read head element | |
US10777222B1 (en) | Two-dimensional magnetic recording (TDMR) read head structure with different stacked sensors and disk drive incorporating the structure | |
US7782575B2 (en) | Magnetoresistive element having free layer, pinned layer, and spacer layer disposed therebetween, the spacer layer including semiconductor layer | |
US7551409B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with improved ferromagnetic free layer structure | |
US7660082B2 (en) | TMR element having a tunnel barrier which includes crystalline portions and non-crystalline portions | |
US7826182B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with CoFeGe ferromagnetic layers | |
US8014109B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with antiparallel-pinned layer containing silicon | |
US8351165B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with CoFeGe ferromagnetic layers and Ag or AgCu spacer layer | |
US8218270B1 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with improved hard magnet biasing structure | |
US20120063034A1 (en) | Current-perpendicular-to-the-plane (cpp) magnetoresistive (mr) sensor with improved insulating structure | |
US6903908B2 (en) | Magnetoresistive effect sensor with barrier layer smoothed by composition of lower shield layer | |
US7599157B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with high-resistivity amorphous ferromagnetic layers | |
US8385025B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with improved seed layer structure for hard bias layer | |
JP2001189503A (en) | Magneto-resistance effect element and magnetic regeneration device | |
US8576519B1 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor with magnetic damping material at the sensor edges | |
CN101067933A (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor | |
US7916430B2 (en) | Thin-film magnetic head and manufacturing method thereof | |
US9047891B1 (en) | Current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) sensor with indium-zinc-oxide (IZO) spacer layer | |
US7450350B2 (en) | Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with antiparallel-pinned structure having segregated grains of a ferromagnetic material and additive Cu, Au or Ag | |
US7215516B2 (en) | Magnetoresistive head having magnetoresistive film including free layer and pinned layer arranged in head height direction | |
US8149547B2 (en) | Magnetoresistive effect element and thin-film magnetic head with the magnetoresistive effect element | |
US7510787B2 (en) | Magneto-resistance effect element and thin-film magnetic head | |
US20080218912A1 (en) | CPP-type magnetoresistive element having spacer layer that includes semiconductor layer | |
US7268977B2 (en) | Capping layers with high compressive stress for spin valve sensors | |
US8054587B2 (en) | Magnetoresistive effect element, thin-film magnetic head with magnetoresistive effect read head element, and magnetic disk drive apparatus with thin-film magnetic head |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: TDK CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIRATA, KEI;MIURA, SATOSHI;REEL/FRAME:019393/0072 Effective date: 20070109 Owner name: TDK CORPORATION,JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HIRATA, KEI;MIURA, SATOSHI;REEL/FRAME:019393/0072 Effective date: 20070109 |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552) Year of fee payment: 8 |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 12TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1553); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 12 |